The Latter Days on Mars:

Plan Summary: On the latter day of the first operated mission to Mars, a crew member of Tantalus Base trusts he has made an amazing discovery – solidified evidence of bacterial life. Loath to let the relief crew claim all the glory, he disobeys orders to pack up and goes out on an unauthorized expedition to collect further samples. But a routine mine turns to disaster when the porous ground failures, and he falls into a deep crevice and near certain death. His devastated colleagues attempt to recover his body. However, when another disappears they start to suspect that the life-form they have open is not yet dead. As the group begins to fall apart it seems their only hope is the pending arrival of the release ship Aurora.

Release date: December 6, 2013 (limited)